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| author | Mathias Stearn <mathias@10gen.com> | 2015-09-04 19:28:39 -0400 |
|---|---|---|
| committer | Mathias Stearn <mathias@10gen.com> | 2015-09-25 18:09:33 -0400 |
| commit | 369164318a5e0c952f3de426a68c48078c64c60c (patch) | |
| tree | 7c4d4e8b4094b956bc70025c192ff6ea0158844a /src/mongo/util/string_map.h | |
| parent | bb235f80e2b9fe431176e0983a6a16aea7674541 (diff) | |
| download | mongo-369164318a5e0c952f3de426a68c48078c64c60c.tar.gz | |
SERVER-20300 Optimize StringMap
Major changes:
* Use 32-bit murmur3 rather than 128-bit
* Use bit-masks rather than modulus
* Default-constructed StringMaps don't allocate memory
* Can no longer configure max probe ratio or default starting size
Diffstat (limited to 'src/mongo/util/string_map.h')
| -rw-r--r-- | src/mongo/util/string_map.h | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/src/mongo/util/string_map.h b/src/mongo/util/string_map.h index 13e93977fcc..ff2946a8f95 100644 --- a/src/mongo/util/string_map.h +++ b/src/mongo/util/string_map.h @@ -29,12 +29,20 @@ #pragma once +#include <third_party/murmurhash3/MurmurHash3.h> + #include "mongo/base/string_data.h" #include "mongo/util/unordered_fast_key_table.h" namespace mongo { -typedef StringData::Hasher StringMapDefaultHash; +struct StringMapDefaultHash { + uint32_t operator()(StringData a) const { + uint32_t hash; + MurmurHash3_x86_32(a.rawData(), a.size(), 0, &hash); + return hash; + } +}; struct StringMapDefaultEqual { bool operator()(StringData a, StringData b) const { |